It has become common practice to use molds to shape certain meat products such as canned hams and other delicatessen meats. These meat products are prepared by placing portions of raw or partially prepared meat in an open container hereinafter referred to as a mold. A lid adapted to telescope into at least an upper portion of the mold is placed over the top of the mold and onto the meat. Springs or other resilient biasing means are used to urge the lid into the mold thereby exerting a pressure on the meat that conforms it to the shape of the mold.
Typically the meat will be cooked while it is in the mold. In order to maximize oven utilization the meat molds and the means used to urge the lid into the mold should take up as little space as possible. Ideally the molding apparatus would have dimensions only slightly greater than the size of the product being molded. Of course some additional height is necessary on the top of the mold to allow for vertical compaction as the meat conforms to the shape of the mold. One problem with a type of apparatus that finds widespread use in the molding of ham is the large amount of additional space required for the apparatus to attach the lid to the mold and urge the lid into the mold.
U.S. Pat. Nos. 2,310,956, 2,310,957, and 2,310,958 issued to F. H. Hoy on Feb. 16, 1943 exemplify the most commonly used type of meat mold. In all of these devices the lid or cover is secured and aligned over the mold by a pin that engages a bore. Both the pin and bore are located outside the periphery of the mold and add substantially to the length of the mold. In addition to the volume taken up by the pin and the bore, more space is needed to accommodate the apparatus for supplying the biasing force to the cover. This apparatus consists of large springs located to the outside of the pin and bore assemblies or compression spring assemblies located on top of one or more molds.
Aside from reducing oven volume by taking up additional space, the pin and bore assemblies and spring tensioning devices have posed operational and safety problems. A relatively tight tolerance must be kept between the pins and bores in order to prevent the lid from tilting while the meat undergoes compaction. As a result sticking and jamming of the lids within the containers or sticking and jamming of a cover assembly for attaching and urging the lid into the mold is a common place occurrence during assembly and disassembly of the molds from the cover assemblies. This sticking and jamming combined with the need to stretch the compression springs over the outside of the molds have led to numerous injuries when loading and unloading the molds. Finally having the compression springs at the outermost ends of the molds, combined with the non-uniformity in the compressibility of the meat pieces across the mold, increases the susceptibility of the mold to produce a final product with an unacceptable degree of dimensional variation over its top surface.
A number of other mold designs are known which attach a meatmold cover to a lip that extends around the outside of the mold. These designs are shown in Rathjen et. al. U.S. Pat. No. 3,646,881, G. Lidseen U.S. Pat. No. 1,720,367, H. Adelman U.S. Pat. No. 1,497,885 and Swiss Pat. No. 158527. The meatmolds in all of these references have covers that are either relatively unstable or require three or more supports to obtain stability. In addition the catches for attaching the covers in all of these references are relatively complex and can be adjusted to a variety of positions which makes their use more difficult.
Vegas U.S. Pat. No. 4,756,505 shows an open basket type meatmold that has cover which engages the sides of the molds over a substantial length of the mold. The cover resiliently biases an engaging rod into the side of the mold to provide a flexible detente. This flexible detente system cannot provide positive downward pressure on the mold product while it is cooking and is designed to be displaced upward by expansion of the mold product. Moreover the design of the flexible detente does not provide uniform pressure to the mold product and therefore cannot promote uniform dimensions for the meatmold product.